Device for extending living tissue

ABSTRACT

A method and apparatus for extending living tissue. The apparatus being surgically implanted in the human body, and in particular beneath the scalp to extend hair producing tissue for reducing baldness. The apparatus includes at least one resilient means with at least two fastening means secured thereto. The fastening means are engageable with the living tissue and extend the tissue under the action of the resilient means. The apparatus is implantable, through a temporary opening, below the surface of the tissue to be extended, and extends the living tissue over a period of time, wherein the apparatus is later removed.

DESCRIPTION

The present invention relates to a device for extending living tissue.

The technical field of the invention is that of making materials thatare surgically implantable in the human body.

One of the main applications of the invention is making extender devicesthat are implantable for a determined length of time beneath the scalpin order to diminish baldness, but other applications can be envisagedfor the device of the invention wherever it is useful and/or necessaryto stretch tissue, e.g. for diminishing wounds where it is necessary tobe able to cover a damaged area with new skin, in particular when theoriginal skin has been destroyed or damaged by burning, trauma, etc. . ..

With respect to so-called "male-pattern" baldness, it is known thatdefinitive hair loss affects one in three of men aged 50.

Such baldness forms a part of a group of conditions known medically as"cicatricial alopecias": it is related to progressive and prematureatrophy of hair follicles, at the roots of individual hairs, and itsorigins are genetic and hereditary.

So far, no medical treatment has managed to treat male-pattern baldness,and no therapeutic solution of a medical kind can be considered earlierthan age 30 to 50.

At present, the only effective therapy is surgical, and more than 2million Americans have had recourse to such surgery: this is done bysurgically redistributing a fraction of healthy follicles that aregenetically programmed to last throughout life. In practice, theyconstitute hair taken from around the tonsure.

For this purpose, essentially there are three techniques, namely:implants; reductions of the tonsure; and flaps; all three of whichconsist in moving healthy hair-carrying scalp to replace all or part ofthe bald scalp.

The present invention relates solely to the second and most recenttechnique of reducing tonsure: it makes it possible to achieve a clearimprovement in results for extensive male-pattern baldness whichconstitute the major fraction of cases to be treated.

This technique consists in eliminating a region of bald skin and inmoving towards each other the two edges of the wound once the surfacessituated beneath the scalp on either side of said wound have beenseparated. The two edges of the wound are then closed together undertension by means of surgical sutures stretching the scalp and therebyincreasing the hair-carrying area at the expense of the bald area.

Thus, on average, it is possible to eliminate a 3 cm wide strip of baldscalp on each operation: four to six tonsure-reducing operations arethen often required since there is a limit to skin resiliency and it isnot reasonable to remove more than 3 cm at a time without running therisk of tearing; nevertheless, in spite of this high number ofoperations, and even if the number is increased, the result cannot beimproved any further, and it is possible in this way to eliminate onlyabout half of the initially bald area.

That failure to reduce the bald scalp area completely is related to twoimportant phenomena that are combined:

There always occurs secondary distension or spreading of 20% to 50% ofthe bald areas close to the region of maximum tension, i.e. where thewound has been sutured, thereby generating a central region that alwaysremains bald: this is well described and specified in the most importantwork on the topic devoted to surgery of the scalp, entitled "Hairtransplantation", 2nd edition of 1987, by Mr. Rolf Norstrom and WalterUnger, in particular at pages 504 to 516, that specify area reductionsin terms of percentages of the areas concerned by tonsure reduction.

A communication form Dr. Richard Shiell in Melbourne, Australia, datedFebruary 1992, given during an international congress on scalp surgeryat Los Angeles gives numerical results of the results of scalp reductionand confirms the limits of said technique.

Damage to or even final disappearance of ischemic hair follicles due totension in the surface layers of the scalp, which disturbs and can slowdown or even completely interrupt blood circulation, thereby giving riseto ischemia of said follicles.

Because of the two above phenomena, it is necessary to associate tonsurereduction operations with implants, thereby increasing both the cost andthe overall duration of the procedure.

To eliminate the above phenomena, balloons placed beneath thehair-carrying scalp have been in use for about 10 years, particularly inAmerica, with the balloons being inflated progressively at regular timeintervals: the hair-carrying scalp is thus subjected to internalpressure and it expands and spreads. Once it is deemed to have expandedsufficiently, the operation can be performed as described above byremoving a strip of the bald region, or even all of it, such that thelips of the remaining regions can be sewn together edge-to-edge, in theproper place.

It is thus possible to eliminate the entire bald area, replacing it withthe hair-carrying regions that have been expanded by the balloons.Nevertheless, it is necessary to expand the balloons themselvesregularly two or three times a week in order to achieve progressiveexpansion without tearing. This requires regular monitoring and, in anyevent, the resulting deformation of the head makes that techniqueunusable on a large scale. Any advantage in that technique is lostbecause of considerations and criteria relating to appearance andbecause of the difficulty in immobilizing people over long periods oftime.

It usually takes several months to obtain a satisfactory result, and sofor a fraction of that period the person concerned must remain isolated.In addition, there is always the danger of a balloon bursting and of theexpansion regions being poorly monitored. These drawbacks give rise to arisk of further surgical intervention during treatment.

The above balloon technique is also common in other surgical treatmentsfor the purpose of obtaining tissue expansion, whenever it is necessaryto produce skin that is then used to cover a loss of substance in apatient, in particular for recovering regions that have been destroyedor damaged after burning or trauma.

One such device is described, for example, in French patent applicationFR 2 615 397 of May 20, 1987 filed by Marseille Assistance Publique foran "ambulatory device for continuous inflation at constant pressure oftissue-expansion balloons" and also in French patent application FR 2608 916 of Dec. 26, 1986 filed by Messrs. Mai and Crassas for a "tissueexpansion prosthesis". In both of those two patent applications, and asin many others throughout the world, there is described essentially aclosed flexible body made of a biocompatible material that is suitablefor expanding under the effect of fluid pressure and that is designed tobe inserted beneath the tissue and/or skin to be repaired.

When the purpose is repair, the unattractive appearance of the balloonsis of minor importance compared with the looked-for objective, even ifthe mobility and the comfort of the persons concerned is in any eventlimited, depending on the location where the balloons have been placed.

Thus, the problem posed is to be able to increase a given area of livingtissue by a determined amount by lengthening it, taking advantage of theability of cells to reproduce, while avoiding unattractive deformationof the volume of the portion of the body covered by said tissue, whilelimiting secondary stretching of the regions that it is not desired tostretch, and with a minimum number of surgical interventions over aperiod of time that is as short as possible.

A solution to the problem posed is a device for extending living tissue,comprising at least one resilient means whose outside dimensions in itsactive position enabling said tissue to be extended are such that aportion of its perimeter corresponds substantially to and is superposedwith the edges of the area of tissue to be treated, and at least twofastening means each secured to a respective end of a resilient means ofthe device, which ends are opposite to each other in the direction ofactive resilience of said resilient means, and enable it to be fixed tosaid tissue along said edges.

In one embodiment, said resilient means may be a flexible part that isplane and of constant or varying thickness, made of an elastomermaterial of the silicone type.

In another embodiment, said resilient means may be constituted by anenvelope made up of two hollow cylindrical portions that are open atleast one end and that slide one within the other, a spring system beingsituated therein so as to enable it to be compressible while tending tomove said portions apart towards a position of maximum separation thatis limited by an abutment system, or else so as to be extensible andtending to move said portions towards each other.

The first embodiment thus serves essentially to apply traction on theends and thus put regions of tissue situated outside the device undertension, even when they are far part from each other, whereas in thefirst type of the second embodiment, the traction effect is applied tothe region of living tissue situated between its ends. One or otherdevice is selected as a function of the type of intervention and of thelooked-for objective. Other resilient means may also be developed forthe application to reducing baldness constituting the main applicationdescribed in the context of the present invention, and also as afunction of other types of application, in particular closing up skin,or recovering regions that have been destroyed or damaged by accident.

The result is novel devices for extending living tissue, satisfying thevarious objects of the problem posed and responding to the variousdrawbacks mentioned above in existing systems, which systems aregenerally devices for expanding volume unlike those described in thecontext of the present invention which can be thought of as extensiondevices or "extenders", since they are concerned with selectivelystretching a surface.

When extension devices of the present invention are used, the advantagesof stretching living tissue such as hair-carrying scalp are obtained inthe same manner as observed when using balloons, however in the presentcase the great advantage is associated with the fact that the stretchingand progressive distortion of the tissue or of the hair-carrying scalpis not obtained by means of an increase in volume, and thus of anincrease in area in all directions, but by an increase of surface areain given directions only. Thus, firstly there are no particular changesto the shape of the head, when the tissue is hair-carrying scalp, andsecondly there is no stretching in directions that are not useful.

In addition, since the active ends of the extension device of thepresent invention can be placed exactly at the edges of the regions thatare to be subjected to traction in order to change their surface area,regions that are not to be stretched are not subjected directly to saidtension. Thus, in the context of stretching hair-carrying scalp, thereis no secondary stretching of bald regions, thereby improving theefficiency of the system and the speed with which it acts. It ispossible to apply traction to hair-carrying regions that are distantfrom the edges of the bald region, so that at the end of extension, andwhen the extender has returned to its rest position, said ends stillbeing at a certain distance apart from each other, the distance betweensaid ends corresponds to the combined width of the hair-carrying regionssituated and held between the ends. A single operation then suffices toachieve the desired result. In addition, there is no destruction offollicles because of ischemia in the surface layers of the hair-carryingscalp, as can be observed in other techniques.

Compared with the basic technique of tonsure reduction, but avoiding theuse of balloons for reasons of appearance, the number of surgicalinterventions is reduced to two, as is theoretically the case when usingballoons, although there is the risk of intermediate interventions,namely one intervention for installing the device and another forremoving it, and this is to be compared with the four to sixinterventions mentioned above.

Compared with the basic technique of reducing tonsure without balloons,it is also possible to emphasize that the overall duration of treatmentis reduced since it is now no more than 1 to 3 months as compared with12 months or more. This is due to the fact that during a singleoperation it is not possible to pull excessively on tissue that providesan initial resistance of more than 15 kg/cm², whereas by applyingtension continuously and progressively, tissues adapt, regenerate, andthus lengthen in a manner that is relatively rapid.

Because of the reduced duration of treatment and the reduced number ofsurgical interventions, the overall cost of treatment is thus greatlyreduced, as is the pain to which the person concerned is subjected,which person is all the more satisfied in that the bald area eliminatedis much greater than it is when performing successive operations becauseof the absence of secondary stretching as mentioned above.

The extension device of the invention is also extremely simple, both asto its design and as to its handling in surgery, thereby making it adevice that is highly advantageous, which is very compact being about 1mm thick for flexible tissue, of constant thickness, but optionallybeing of varying thickness, and it is gently and smoothly "shapeable" tofit to any head.

It can thus be used for any case of extensive baldness, and also in allof the other applications mentioned above.

Further advantages of the present invention could also be mentioned,however those mentioned above already suffice to demonstrate the noveltyand the advantage of the invention.

The following description and figures show embodiments of the inventionbut they are not limiting in any way: other embodiments are possiblewithin the ambit of the scope and the extent of the present invention,in particular by changing the shape and the type of the resilient means,and also the shape and the type of the fastening means.

FIG. 1A is a diagrammatic perspective view of the device of theinvention implanted on the head.

FIG. 1B is a fragmentary section view of the fastening of the devicebeneath the scalp.

FIG. 2A is a plan view of an embodiment of the device.

FIG. 2B is a side view of the FIG. 2A device.

FIG. 2C is a perspective view of a two-part device having a centralfastening.

FIG. 2D is a perspective view of a device having a suture support.

FIG. 3A is a plan view of another device implemented by combiningresilient means.

FIG. 3B is a side view of the FIG. 3A device.

FIG. 3C is a side view of the device of FIGS. 3A and 3B, but shown invarying thickness.

FIGS. 4A and 4B are perspective views of two embodiments of the devicefor installing the device of the invention.

FIGS. 5A and 5B are two perspective views of two other embodiments ofthe device of the invention made of a flexible material.

FIG. 6A is a perspective view of another embodiment of the device of theinvention.

FIG. 6B shows a device made by hinging together devices as shown in FIG.6A.

FIG. 7 shows various other embodiments of the fastening system.

FIG. 1A is a diagrammatic perspective view of the head of a person whosescalp includes a bald region 1 and hair-carrying regions 3 situated atthe periphery of said bald region 1.

The extension device 2 of the present invention is then disposed beneathsaid scalp, by incision of an opening 14 in the middle of said baldregion 1. The fastening systems situated at the two opposite ends of thedevice 2 shown herein as being in the form of a rectangle as shown inFIG. 2A, and constituted by hooks 7, for example, are anchored in thegalea 6 and in the hypoderma, that is to say the rigid fiber layerconstituting the deepest portion of the scalp, shown in section in FIG.1B.

Said fastening systems which may thus be installed along the edges 13 ofa portion at least of the area of tissue to be treated, and in this casethe example is the scalp where the purpose is to move the hair-carryingregions 3 towards each other. The edges 13 are not necessarily at theboundary 16 between the hair-carrying regions 3 and the bald region 1.It is preferable, as mentioned above, to apply traction to hair-carryingregions that are distant from the edges of the bald region so that atthe end of extension and when the extender 2 has returned to its restposition, said ends still being at a certain distance apart from eachother, the distance between said ends corresponds to the combined widthof the hair-carrying regions 17 situated between the ends. Thisdistribution of traction over the hair-carrying regions that are to betreated may be performed more completely and more effectively using thedevice shown in FIGS. 3.

It is not necessarily useful or necessary to apply uniform andcontinuous force to the entire length of the edges 13 of the area to betreated, and traction and fastening may be applied to a portion only innonadjacent regions thereof, depending on the state of the tissue and onthe desired result, with this being made possible, for example, by anextension device of the kind shown in FIG. 5B. Adjacent regions lyingbetween two points or two lines of traction are entrained indirectly toa greater or lesser extent depending on the disposition of the fasteningsystems 7, and in this way, even when applying traction only to aportion of the edges 13 of the region to be treated, the entire regionwill be subjected to the extension effect, but in a manner that isselective, determined, and defined, thus enabling the best possibledesired result to be obtained.

In the example of FIG. 1A, the extension device is a resilient device,also referred to as an extender, made of plane flexible parts ofsilicone type elastomer material, and it is put under tension while itis being installed by means of tools of the kind shown in FIGS. 4.Thereafter it contracts progressively in the direction of its activeresiliency XX' in which force was initially applied, so as to return toits initial length, thereby moving its ends towards each other and thusalso moving the fastening systems 7, thus tending to move said edges 13towards each other while compressing the bald region 1 and, depending oncircumstances, also compressing a fraction 17 of the hair-carryingregions situated between the fastening systems, as mentioned above.Confidential experiments have shown that such extension-compressiontakes place over a period of time that is of the order of 1 month to 2months.

The scar 14 that enables the said device to be installed can then bereopened so that the device can be removed and so as to cut off the baldstrip 1 which is then naturally in excess, after which the edges 16 canbe sewn directly to each other.

The looked-for effect is thus obtained and no further surgicalintervention is required. Throughout the entire duration of stretchingand activity of the device, it remains invisible from the outside, andall that can be seen is a small amount of folding of the skin, whichdoes not greatly change the appearance of the person who can thereforecontinue being active without being obliged to isolate himself from hisenvironment as is the case with balloons.

FIG. 1B is a section view through the scalp in which the device of theinvention has been anchored by one of its fastening systems 7 engagingin the galea and the hypoderma 6, i.e. the fibrous surface situatedbeneath the scalp 5 proper, itself protected by the outer skin 4. In theexample of FIG. 1A, the fastening systems 7 tend to pull the edges 13 ofthe outer region to be treated 3 by applying traction thereto, whereasthe region situated between said edges 13 is subjected, on the contrary,to compression.

In the example of the device of the invention shown in FIGS. 6A and 6B,the fastening systems are situated in the opposite direction to theabove, so as to provide fastening that makes it possible, on thecontrary, to apply tension to the region situated between the fasteningsystems while applying compression to the regions situated outside them,with this being made possible by a compression spring 10 that tends tourge the fastening systems apart.

FIG. 2A is a plan view of a device as implanted in the manner shown inFIG. 1A, in which said resilient means 8 is a flexible piece of siliconetype elastomer material. FIG. 2B is a side view of such a device withsaid piece being flexible, plane, and of constant width and thickness,however it could also be of varying width and/or thickness as shown inFIGS. 3C and 3B, for example. In this figure, said piece is made of atleast two separable portions each corresponding to and carrying one ofsaid fastening means 7 at one end of the device, and said separableportions are united by an appropriate link means 9. Said link means mayhave three functions:

firstly, to enable the device to be installed in at least two mutuallyindependent portions by hooking the end systems in the tissue to betreated and then by putting the two portions under tension endconnecting them together by means of said device 9, without requiringthe use of external means such as those shown in FIG. 4;

secondly, to be able to receive an adhesive or suture reinforcing systemsuch as that shown in FIGS. 2B and 2D so as to enable the bald region 1that is compressed by said device to be kept "glued" or sutured to thesurface without any risk of large ugly folds being made that rise upunder the effect of the compression; and

finally, to be able to be made of a material that is stronger than theresilient piece 8 so as to make it possible during possible intermediatesurgery to cut the scalp without running the risk of cutting saidresilient piece, as shown in FIG. 2D. In this figure there can be seenreinforcement 9 for the suture that can be used even with a one-pieceextender 8.

Said suture reinforcing or link piece 9 may be made of polyester typecloth or of metal-coated polyethylene plates, or of any other strongbiocompatible material. It may either cover the two ends of the twoportions in the middle of the extender 8, as shown in FIGS. 2A, 2B, or2D, or else said link piece 9 may be made up of two elements eachconnected to one of the ends of said two portions of the extender, asshown in FIG. 2C so as to form a central fastening system.

FIGS. 3A and 3B constitute a plan view and a side view of anotherembodiment of the extension device of the present invention forextending living tissue, comprising a plurality of resilient means 8 ofthe above type constituted by independent plane superposable flexiblepieces of constant or varying thickness and of different dimensions,with the largest piece being placed furthest from the surface of saidtissue to be treated, the next largest piece being placed against thepreceding piece, between it and the tissue to be treated, and so on upto the smallest piece which is thus directly in contact with said tissueover its entire area.

Such a device thus makes it possible to apply force along differentlines of traction to a plurality of regions of tissue to be treated,thereby achieving better distribution of tensions and/or of differentforces so as to obtain different amounts of tissue extension indifferent regions. Thus, when treating baldness, the hair-carryingregions 3 may have different densities of hair, and it is thus possibleto make hair density more uniform.

For the same purpose, the plane flexible pieces constituting saiddevices may be made of varying widths and thicknesses, so as to applymore or less force to various regions of the living tissue. This makesit possible to have either a single resilient flexible piece on whichfastening systems 7 can be secured in different locations, as shown inFIG. 3C, without any need for superposed layers of pieces as shown inFIGS. 3A and 3B, or when using such superposed layers as shown in FIGS.3A and 3B, to obtain complex selective stretching effects. This is inaddition to and combined with the possibility of disposing fasteningsystems at selected points in a continuous line as shown in FIGS. 2 and3, or in a discontinuous line as shown in FIGS. 5, all along the edges13 of the region to be treated or over a portion only thereof, asmentioned above and below.

FIGS. 4A and 4B are perspective views of two examples of tools forinstalling the extension device constituted by resilient means 8.

In FIG. 4A, it is shown in the rest position prior to being extended andshaped, e.g. to the shape of a head, by means of an installation tool15. It is pressed against the portion of the body whose shape is to betaken up by the resilient piece 8 by elastic deformation thereof undertraction, until said fastening systems 7 reach the edges 13 of the areaof tissue to be treated and are hooked thereto, thereby enabling saidtool 15 to be withdrawn. However the tool is not necessary when saidflexible piece is made up of two mutually separable portions as shown inFIGS. 2A and 2B.

FIG. 4B shows another tool 17 suitable for installing the fasteningsystems 7 one after the other. It comprises a tip 20 for engaging insaid hooks or fastening systems 7, like the tool in FIG. 4A, which tipis at the end of a handle 19, and it includes a hinged lever 18 whoseshape makes it possible to detach the scalp or other living tissuebeneath which said extender 8 is to be slid, with this being done bypressing the lever against said handle 19 of the tool. Thus, this toolserves not only to install the extender, but also makes it possible toremove it in a manner that is relatively simple and practical.

FIGS. 5 show other examples of devices of the invention in which saidresilient means 8 include three fastening means 7. In FIG. 5A, two ofthe fastening means 7 are situated in opposite directions to each otheras in the preceding figures, while the third fastening means extendsalong a perpendicular direction, thus making it possible, for example,also to pull in a hair-carrying region from the back of the scalp,should that be necessary. In FIG. 5B, the three fastening means 7 shownin fact constitute a single fastening means 7 according to the precedingdefinition, situated on one side only of a single end of the resilientmeans 8, however the fastening means extend along lines that are notcontinuous relative to one another, thereby causing certain regions tobe subjected to greater force than others, it being understood that theintermediate regions are subjected to indirect force as explained above.

It is also possible to make other devices with four, five or even morefastening devices depending on the desired objective, said devices 7possibly following straight lines as shown in FIGS. 1 to 6 and 7A and7D, however they could also follow curved lines as shown in FIGS. 7B and7C, or they could have any other continuous or discontinuous line shapeas mentioned above, depending on the regions that are to be subjected totraction relative to the entire region to be treated, as a function ofthe looked-for result and of the initial situation.

FIGS. 6A and 6B show another embodiment of the device of the inventionin which said resilient means 8 is constituted by an envelope 11 made upof two mutually slidable, semi-closed portions containing an appropriatespring system 10 that is either compressible, tending to move apart saidportions to a position of maximum separation that is defined by someappropriate abutment system, or else is extensible tending to move saidportions towards each other. In the first type, the fastening systems 7are directed outwardly relative to the device, as shown in FIG. 6A,whereas in the second type they are directed inwardly as shown in FIGS.1 to 5. In FIG. 6B, the device of the invention comprises a plurality ofenvelopes 11 that are hinged to one another about axes 12 enabling theset of said envelopes 11 to be fitted over the natural shape of theliving tissue to be treated.

FIG. 7 shows a plurality of embodiments of the fastening system 7, whichsystem may be constituted by hooks, claws, clamps, or any other linkingmeans capable of anchoring in living tissue and transmitting the tensionof the resilient means 8, and having a system suitable for connectingthem to said resilient means in the particular configuration thereof,e.g. by clamping, by welding, by sewing, by snap-fastening, etc. . . .

Devices of the invention may also be implanted externally, under thecondition that when reducing baldness as in the above-specifiedapplication, the hooks are placed in the galea itself, passing throughthe entire thickness of the scalp so as to cause it to move and obtainthe looked-for result, even though appearance will not be good giventhat the device of the invention can be seen from the outside, howeverit may possibly be camouflaged by a portable wig while such compressiontraction is taking place since there is no change in volume per se, andthere is no need to perform a surgical operation to install the device.

In other applications, devices of the invention can be used wheneverthere is a need to tension or stretch the area of a tissue that isstrong enough to avoid tears or breaks of the fibers, and whenever saidstretching of tissue is desirable.

What is claimed is:
 1. A device for extending living tissue having adeep fibrous layer, the device surgically implantable under the livingtissue, the device comprising at least one resilient means and at leasttwo fastening means, each fastening means coupled to a respective end ofthe resilient means, whose outside dimensions, in its active position,are such that a portion of its perimeter corresponds substantially toand is supported with edges of an area of tissue to be treated, whereinsaid resilient means is constituted by an envelope made up of two hollowcylindrical pieces that are open at least one end that slide one in theother, a compressible spring system being placed therein and tending tomove said pieces apart to a position of maximum separation limited by anabutment system, the fastening means being fixable to the rigid fibrouslayer near the edges of the tissue, which ends of the resilient meansare opposite to each other in the direction of active resilience of saidresilient means.
 2. The extension device for living tissue according toclaim 1, wherein the device is made up of a plurality of envelopes thatare hinged to one another about axes enabling said envelopes to follow anatural shape of the living tissue to be treated.